Add ability to view and manage member access across entire Group including folders and projects

Proposal

Add the capability for users with admin access to view member access across the entire group, including folders and projects within the group.

Problem statement: Using Gitlab for our engineering team, we have many folders and projects. We don't want to grant access to everyone for everything, so we have to add member access at a folder or project level. When someone leaves, we have to manually comb through the folders and proejcts to revoke their access. If we had a way to view at a top level all members with access to anything in our group, we could go to a single place to view and revoke their access. Also would be useful from a security and audit perspective.

What does success look like:

Members with group level admin access can view and update other members access to any folder or project from a single location.